From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Letter to Lodge Plugs Ltd regarding the unsatisfactory performance of S.I type plugs in experimental high compression engines.
| Identifier | ExFiles\Box 162\6\ img125 | |
| Date | 16th March 1932 | |
| Kestrel S Chassis. Hs{Lord Ernest Hives - Chair}/Lid.{A. J. Lidsey}5/MA. March 16th, 1932. Messrs. Lodge Plugs Ltd., Rugby. For the Attention of Mr. Bernard Hopps. Dear Sirs, With reference to the S.I type Lodge plug, several sets of which we are using in our experimental cars we have to inform you that the results obtained are not altogether satisfactory. Their failing appears to be under full throttle low speed conditions in high compressions engines (above 5:1). We have had no trouble at all in our standard Compression engines and they appear quite good and show no signs of preigniting at high speeds when used in high compression engines. We are returning to you three plugs which gave trouble on the road and which when tested under 80 lbs/sq.in. compression failed to spark under conditions of ignition that produces a spark when testing a standard C type plug similarly. We shall be interested to have your remarks on the subject. Yours faithfully, FOR ROLLS ROYCE LIMITED. P.S. One of the three plugs you will notice has a broken porcelain, this we think has been accidentally broken 'after' the plug failed. | ||